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R C Gupta

Publications and source records attributed to R C Gupta.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous quantification of alpha-/beta-diastereomers of arteether, sulphadoxine and pyrimethamine: a promising anti-relapse antimalarial therapeutic combination, by liquid chromatography tandem mass spectrometry.

A rapid, sensitive, selective and specific HPLC/ESI-MS/MS assay method was developed and validated for the simultaneous quantitation of alpha-/beta-diastereomers of arteether (AE), sulphadoxine (SDX) and pyrimethamine (PYR) in rat blood plasma using propyl ether analogue of beta-arteether as internal standard. The method involved a single-step, liquid-liquid extraction with ethyl acetate and the analytes were chromatographed on a C18 chromatographic column by isocratic elution with methanol:ammonium acetate buffer (10 mM, pH 4) (90:10%, v/v) and analyzed by tandem mass spectrometry. The run time was 4.5 min and the weighted (1/x2) calibration curves were linear over a range of 0.78-400 ng ml-1. The method was validated fully and the lower limit of quantification (LLOQ) in plasma was 0.78 ng ml-1 for all the analytes. The intra- and inter-day precision and accuracy were found to be well within the acceptable limits (<15%) and the analytes were stable after three freeze-thaw (f-t) cycles. The absolute recoveries were consistent and reproducible. The assay method was applied to pre-clinical pharmacokinetic interaction studies of alpha-/beta-AE, SDX and PYR in rats.

Animals↗
PubMed2006

Role of taurine in spinal cord injury.

Taurine is a sulfur amino acid. It is found endogenously in human and several others tissues. It is significantly in high concentration in mammals. Human body contains about 0.1% of body weight as taurine. It has a number of physiological and pharmacological actions. It is also used in the therapy of important organs dysfunctions. In spinal cord it has inhibitory effects; like antiepileptic and anti-nociceptive. Taurine also inhibits substance p induced biting and scratching behavior. In spinal cord injury elevated level of taurine has been observed. Higher level of taurine has been also recorded in SCI therapy using, known clinical agent methyl prednisolone (MP). The increased taurine concentration seems to be involved in protection and regeneration of tissues following injury. In SCI along with physical injury secondary activities also takes place which are complex in nature. Secondary activity includes vascular events and activation of neutrophils, resulting endothelial damage. Activated neutrophils; release a variety of inflammatory mediators such as myeloperoxidase (MPO), reactive oxygen species (ROS), and some others. It is believed that taurine exert its protective action through scavenging of ROS and down regulating several other inflammatory mediators like tumor necrosis factors (TNFalpha). The inside of mechanism reveals toxic substance HOCl is produced by MPO is converted to less toxic substances through scavenging action of taurine. Amino acid therapy has its own limitations and to over come such situation there is a need to develop small, simple lipophilic analogs of taurine. Use of taurine analogs has provided better results; for example, N- chloro taurine (NCT) which is a taurine derivative has exhibited therapeutic advances over taurine. Taurine and its analogs with sound experimental and clinical support may constitute a new class of therapeutic agents for SCI., and perhaps this review may provide enough material to think of this.

Animals↗
PubMed2005

A sensitive and selective HPLC/ESI-MS/MS assay for the simultaneous quantification of 16-dehydropregnenolone and its major metabolites in rabbit plasma.

A sensitive, selective and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous quantification of 16-dehydropregnenolone (DHP) and its five metabolites 4,16-pregnadien-3, 20-dione (M(1)), 5-pregnene-3beta-ol-20-one (M(2)), 5-pregnene-3beta, 20-diol (M(3)), 5-pregnene-3beta-ol-16, 17-epoxi-20-one (M(4)) and 5,16-pregnadien-3beta, 11-diol-20-one (M(5)) in rabbit plasma using dexamethasone as internal standard (IS). The analytes were chromatographed on Spheri-5 RP-18 column (5 microm, 100 mm x 4.6 mm i.d.) coupled with guard column using acetonitrile:ammonium acetate buffer (90:10, v/v) as mobile phase at a flow rate of 0.65 ml/min. The quantitation of the analytes was carried out using API 4000 LC-MS-MS system in the multiple reaction monitoring (MRM) mode. The method was validated in terms of linearity, specificity, sensitivity, recovery, accuracy, precision (intra- and inter-assay variation), freeze-thaw, long-term, auto injector and dry residue stability. Linearity in plasma was observed over a concentration range of 1.56-400 ng/ml with a limit of detection (LOD) of 0.78 ng/ml for all analytes except M(3) and M(5) where linearity was over the 3.13-400 ng/ml with LOD of 1.56 ng/ml. The absolute recoveries from plasma were consistent and reproducible over the linearity range for all analytes. The intra- and inter-day accuracy and precision method were within the acceptable limits and the analytes were stable after three freeze-thaw cycles and their dry residues were stable at -60 degrees C for 15 days. The method was successfully applied to determine concentrations of DHP and its putative metabolites in plasma during a pilot pharmacokinetic study in rabbits.

Animals↗
PubMed2005

A sensitive and selective LC-MS-MS method for simultaneous determination of picroside-I and kutkoside (active principles of herbal preparation picroliv) using solid phase extraction in rabbit plasma: application to pharmacokinetic study.

A rapid, sensitive and selective LC-MS-MS method for the simultaneous quantitation of picroside-I and kutkoside (active constituents of herbal hepatoprotectant picroliv) was developed and validated in rabbit plasma. The analytes and internal standard (Amarogentin) were extracted using Oasis HLB solid phase extraction cartridges. Analysis was performed on Spheri RP-18 column (10 microm, 100 mm x 4.6 mm i.d.) coupled with guard column using acetonitrile:MilliQ water (50:50, %v/v) as mobile phase at a flow rate of 1 ml/min with a retention time of 1.39, 1.33 and 1.42 min for picroside-I, kutkoside and amarogentin, respectively. The quantitation was carried out using an API-4000 LC-MS-MS with negative electro spray ionization in multiple reaction monitoring (MRM) mode. The precursor to product ion transitions for picroside-I, kutkoside and amarogentin were m/z 491 > 147, 199; 511 > 167, 235; 585 > 227, respectively. The method was validated in terms of establishing linearity, specificity, sensitivity, recovery, accuracy and precision (within- and between-assay variation), freeze-thaw (f-t), auto injector and dry residue stability. Linearity in plasma was observed over a concentration range of 1.56-400 ng/ml with a limit of detection (LOD) of 0.5 ng/ml for both analytes. The recoveries from spiked control samples were > 60 and > 70% for picroside-I and kutkoside, respectively. Accuracy and precision of the validated method were within the acceptable limits of < 20% at low and < 15% at other concentrations. The analytes were stable after three freeze-thaw cycles and their dry residues were stable at -60 degrees C for 15 days. The method was successfully applied to determine concentrations of picroside-I and kutkoside post i.v. bolus administration of picroliv in rabbit.

Animals↗
PubMed2005

A high throughput approach for simultaneous estimation of multiple synthetic trioxane derivatives using sample pooling for pharmacokinetic studies.

The present study describes the application of concept of sample pooling to increase the throughput of pharmacokinetic screening at drug discovery and development stage. An HPLC-UV method for the simultaneous estimation of three synthetic antimalarial compounds 99/357, 99/408 and 99/411 has been developed and validated in rat serum with internal standard for pharmacokinetic profiling. Drug compounds in serum were extracted by two-step liquid-liquid extraction with 2% isopropyl alcohol in n-hexane and quantitated using a validated gradient HPLC-UV method, which was made feasible for all compounds using gradient elution scheme. The method was validated in terms of HPLC reproducibility, linearity, specificity, recovery, accuracy and precision, freeze thaw stability and long-term storage stability. Excellent linear relationships (r>0.99) were obtained for calibration as well as analytical standards over a concentration range of 25-1000 ng/ml for three analytes. Recoveries were fond to be >85% for 99/408 and 99/357 and >70% for 99/411. The method developed for three analytes was found to be accurate and precise as bias and percent relative standard deviation (% R.S.D.) values were within limits (<20%). By employing sample pooling approach, plasma level - time profile following single intravenous dose of all three compounds were obtained in a fraction of the time required by conventional single compound dosing and analysis.

Animals↗
PubMed2005

Pharmacokinetics of the diastereomers of arteether, a potent antimalarial drug, in rats.

The pharmacokinetics of alpha- and beta- diastereomers of arteether, a potent erythrocytic schizontocidal agent, and their active metabolite dihydroartemisinin were studied in male Sprague-Dawley rats after oral, intramuscular and intravenous administrations. Oral and intramuscular studies were carried out at three dose levels at 9, 17.5 and 30 mg kg(-1). The ratio of alpha- and beta-isomers was maintained at 30:70% w/w in the formulations used for the study. The average oral bioavailabilities of alpha-and beta-isomers, relative to intramuscular administration, were 9.6% and 3.8%, respectively, and the average in vivo alpha- to beta- ratio was 2.5. Following intravenous and intramuscular administrations the in vivo alpha- to beta- ratios were 0.7 and 0.9, respectively. The beta-isomer of arteether was characterized by a longer elimination half-life and a relatively larger volume of distribution than the alpha-isomer, suggesting that beta-arteether may be responsible for the prolonged in vivo schizontocidal activity. The alpha-isomer was absorbed rapidly after oral and intramuscular administrations and showed higher peak plasma concentrations but possessed a relatively shorter half-life. There was an apparent lack of linearity observed in terms of dose and AUCs for both alpha- and beta-arteether after oral and intramuscular administrations, suggesting nonlinear dose dependent pharmacokinetics at the dose levels studied. The rate and extent of conversion of arteether isomers to dihydroartemisinin was highest with oral and intravenous administration and least with intramuscular indicating that the intramuscular route of administration of the isomeric mixture may be more beneficial for malarial chemotherapy.

Administration, Oral↗
PubMed2005

Efficacy and safety of glycosylated undenatured type-II collagen (UC-II) in therapy of arthritic dogs.

DeParle L. A., Gupta R. C., Canerdy T. D., Goad J. T., D'Altilio M., Bagchi M., Bagchi D. Efficacy and safety of glycosylated undenatured type-II collagen (UC-II) in therapy of arthritic dogs. J. vet. Pharmacol. Therap.28, 385-390. In large breed dogs, arthritis is very common because of obesity, injury, aging, immune disorder, or genetic predispositions. This study was therefore undertaken to evaluate clinical efficacy and safety of undenatured type-II collagen (UC-II) in obese-arthritic dogs. Fifteen dogs in three groups received either no UC-II (Group I) or UC-II with 1 mg/day (Group II) or 10 mg/day (Group III) for 90 days. Lameness and pain were measured on a weekly basis for 120 days (90 days treatment plus 30 days post-treatment). Blood samples were assayed for creatinine and blood urea nitrogen (markers of renal injury); and alanine aminotransferase and aspartate aminotransferase (evidence of hepatic injury). Dogs receiving 1 mg or 10 mg UC-II/day for 90 days showed significant declines in overall pain and pain during limb manipulation and lameness after physical exertion, with 10 mg showed greater improvement. At either dose of UC-II, no adverse effects were noted and no significant changes were noted in serum chemistry, suggesting that UC-II was well tolerated. In addition, dogs receiving UC-II for 90 days showed increased physical activity level. Following UC-II withdrawal for a period of 30 days, all dogs experienced a relapse of overall pain, exercise-associated lameness, and pain upon limb manipulation. These results suggest that daily treatment of arthritic dogs with UC-II ameliorates signs and symptoms of arthritis, and UC-II is well tolerated as no adverse effects were noted.

Administration, Oral↗
PubMed2005

Taurine analogues; a new class of therapeutics: retrospect and prospects.

Taurine was discovered more than two hundred years ago from animal sources. It is distributed in both mammals and non-mammals and its content is high in several tissues. For more than a century-and-a-half, taurine was regarded just as an end product of sulfur metabolism. Recently, taurine has been rediscovered and its beneficial effects in processes like epilepsy, hypertension, congestive heart failure and diabetes have been well-documented. It was patented and found some clinical utility, but being an amino acid, therapeutic use confronts limitations like restricted permeability and more. This necessitates the development of pro-drugs (analogues) mainly derivatives of taurine. A large number of taurine derivatives have been reported in the literature with partial to marked activity. Taurine derivatives like taltrimide, acamprosate and tauromustine, are already in the market as anti-convulsant, anti-alcoholic and anti-cancer agents. Many other analogues are effective in experimental models. The in depth analysis of these analogues and their biological actions can provide certain clues for further consideration. In the present review, attempts have been made to provide synopsis, synthesis and symbiosis of chemical and biological actions, which may provide future guidance and facilitate further research in this area. The successful journey of these analogues to clinical utility is a healthy and happy sign and an index of bright future, and we hope that this review will provide enough input to ignite the minds.

Animals↗
PubMed2004

HPLC-UV method for assaying 99/357, a synthetic trioxane antimalarial derivative in rat and rabbit serum.

In the present study an accurate and precise HPLC-UV assay method in rat and rabbit serum has been developed and validated for determination of 99/357--a new synthetic analogue of artemisinin developed by Central Drug Research Institute (CDRI), of the class of trioxane derivative. Separation was achieved using a C-18 reversed phase column with a mobile phase comprising of acetonitrile and deionized water (80:20%, v/v) using a UV detector, set at a wavelength of 266 nm. The method, applicable to 200 microl serum, involved double extraction of the samples with 20% isopropyl alcohol (IPA) in n-hexane. The recovery of 99/357 in the two matrices was >90%. The method was sensitive with a limit of quantitation of 25 ng/ml in both rat and rabbit matrices. Precision and accuracy were within the acceptable limits, as indicated by relative standard deviation (accuracy) varying from -12.7 to 5.7% and bias (precision) values ranging from 0.6 to 11.8%. Moreover, 99/357 was stable in serum up to 30 days of storage at -60 degrees C and after being subjected to three freeze/thaw cycles. The method will be applied to perform pharmacokinetic studies of 99/357.

Animals↗
PubMed2004

Analysis of changes in energy and redox states in HepG2 hepatoma and C6 glioma cells upon exposure to cadmium.

The energy and redox states of the HepG2 hepatoma and the C6 glioma cells were studied by quantifying the levels of ATP, ADP, AMP, GSH, and GSSG. These values were used to calculate the energy charge potential (ECP = [ATP + 0.5ADP]/TAN), total adenosine nucleotides (TAN = ATP + ADP + AMP), total glutathione (TG = [GSH + GSSG]/TAN), and the redox state (GSH/GSSG ratio). For comparison between cell types, the level of each energy metabolite (ATP, ADP, and AMP) was normalized against TAN of the respective cell. The results showed that ATP:ADP:AMP ratio was 0.76:0.11:0.13 for the HepG2 cells and 0.80:0.11:0.09 for the C6 glioma cells. ECP was 0.81 +/- 0.01 and 0.85 +/- 0.01 for the HepG2 and the C6 glioma cells, respectively. GSH/GSSG ratio was 2.66 +/- 0.16 and 3.63 +/- 0.48 for HepG2 and C6 glioma cells, respectively. TG was 3.2 +/- 0.54 for the HepG2 cells and 2.43 +/- 0.18 for the C6 glioma cells, indicating that the level of total glutathione is more than two to three times higher than the total energy metabolites in these cell lines. Following a 3-h incubation in medium containing different concentrations of Cd, there was a dose-dependent decrease in cell viability. The 3-h LC50 for the HepG2 cells was 0.5 mM and that for the C6 glioma cells was 0.4 mM. Cellular TAN decreased with a decrease in cell viability. Upon careful analysis of the energy state, there was a significant increase in relative amount of ATP and decrease in ADP and AMP in both cells as Cd concentration increased from 0 to 0.1, 0.2, and 0.6 mM. However, ECP in both cell lines increased, which indicated that the level of high energy phosphate was adequate. There was also a significant increase in TG and a significant decrease in GSH/GSSG in the C6 glioma cells when cells were exposed to as low as 0.1 mM Cd, which suggested that the cellular redox state was compromised. The HepG2 cells, on the other hand, showed no significant change in both TG and GSH/GSSG level until Cd concentration reached 0.6 mM. Results of the present study also showed that there were differences between the two cells in response to the same level of Cd exposure. The C6 glioma cells were more sensitive to Cd-induced injuries. Although there was a decrease in total amount of high energy phosphate as cell viability decreased, the surviving cells were not devoid of high energy phosphates. The relative abundance of ATP amongst the adenosine nucleotide pool and the increase in ECP could be interpreted as a way the cells signal the conservation of energy utilization in response to the damaged mitochondrial function. This move for energy conservation might be the cause of eventual cell death through the process of apoptosis.

Adenine Nucleotides↗
PubMed2004

Pattern profiling of the herbal preparation picroliv using liquid chromatography-tandem mass spectrometry.

At present, the construction of chromatographic fingerprints of complex herbal preparations in combination with mass spectrometry plays an important role in their development and standardization as potential therapeutic agents. Picroliv, an extract from roots and rhizomes of Picrorhiza kurroa, is a herbal hepatoprotective developed by CDRI. We report for the first time pattern profiling of various constituents of picroliv along with a precise and accurate method to estimate relative concentration of major components in the preparation by liquid chromatography-tandem mass spectrometry. In total, 27 components could be detected in multiple reaction monitoring (MRM) mode out of which fourteen could be quantified in terms of their relative concentration. Seven components were structurally correlated and confirmed based on the fragmentation pattern and information available in literature. The detection was carried out using MRM in negative ionization mode with analytes quantified from the summed total ion value of their most intense molecular ion transitions. The separation of various components was achieved using a gradient elution on RP-18 column with acetonitrile and Milli-Q water as mobile phase at a flow rate of 1.0 ml/min. The method was validated in terms of linearity, accuracy and precision (within- and between-assay variation) for 5 days. Linearity range was different for various components depending upon their sensitivity and abundance in the herbal preparation. Within- and between-assay accuracy (%bias) and precision (%R.S.D.) were within acceptable limits. The method was successfully applied to detect and determine relative concentrations of various components in two different batches of picroliv.

Chromatography, Liquid↗
PubMed2004

Clinical profile and outcome of stroke in relation to glycaemic status of patients.

The present study was undertaken in 50 patients of acute stroke to assess the role of glycaemic status on clinical profile and outcome of stroke. Subjects were divided into two groups: Group 1--Comprising of 25 patients of acute ischaemic stroke; Group 2--Comprising of 25 patients of acute haemorrhagic stroke. Each group was subdivided into euglycaemics, stress hyperglycaemics, newly diagnosed diabetics and known diabetics subgroups (stress hyperglycaemics, newly diagnosed diabetics and known diabetics together were called hyperglycaemics). Hyperglycaemics of both the groups had larger sized stroke. Neurological assessment done at day 1 and day 10 by Gillory's scoring system showed statistically significant improvement (P < 0.01) in all neurological functions in the euglycaemic subgroup in both the groups while in the hyperglycaemic subgroup improvement in higher mental function and motor function was insignificant (P > 0.05). There was statistically significant mortality (P < 0.05) (up to 10th day) with the hyperglycaemic subgroup in both the groups as compared to the euglycaemic subgroup.

Acute Disease↗
PubMed2003

HPLC-UV method development and validation for 16-dehydropregnenolone, a novel oral hypolipidaemic agent, in rat biological matrices for application to pharmacokinetic studies.

An accurate and precise HPLC assay has been developed and validated for determination of dehydropregnenolone (DHP) in rat plasma, bile, urine and feces. Separation was achieved using a C-18 reversed phase column with a mobile phase comprising of acetonitrile and deionized water (55:45% v/v) using a UV detector, set at a wavelength of 248 nm. The method, applicable to 200-microl plasma, bile and urine, involved double extraction of the samples with n-hexane. The sample clean up for feces involved single extraction of 50 mg of sample with 3 ml of acetonitrile. The method was sensitive with a limit of quantitation of 20 ng/ml in all the matrices and absolute recovery >92%. Precision and accuracy were within the acceptable limits, as indicated by relative standard deviation varying from 4.7 to 11.2% and bias values ranging from 1.8 to 8.8%. Moreover, DHP was stable in plasma, bile and urine up to 90 days of storage at -60 degrees C and after being subjected to three freeze-thaw cycles. The method was applied to generate the pharmacokinetics of DHP in rats after oral and intravenous administration.

Administration, Oral↗
PubMed2003

Liquid chromatography-tandem mass spectrometric assay with a novel method of quantitation for the simultaneous determination of bulaquine and its metabolite, primaquine, in monkey plasma.

A sensitive and selective liquid chromatography-tandem mass spectrometry method (LC-MS-MS) for the simultaneous estimation of bulaquine and primaquine has been developed and validated in monkey plasma. The mobile phase consisted of acetonitrile/ammonium acetate buffer (20 mM, pH 6) (50:50 v/v) at a flow-rate of 1 ml/min. The chromatographic separations were achieved on two spheri cyano columns (5 microm, 30 x 4.6 mm I.D.) connected in series. The quantitation was carried out using a Micromass LC-MS-MS with an electrospray source in the multiple reaction monitoring (MRM) mode. The analytes were quantified from the summed total ion value of their two most intense molecular transitions. This is another novel method leading to increased sensitivity and precision. A simple liquid-liquid extraction with 2 x 1.0 ml n-hexane/ethyl acetate/dimethyloctyl amine (90:10:0.05, v/v) was utilized. The method was validated in terms of recovery, linearity, accuracy and precision (within- and between-assay variation). The recoveries from spiked control samples were >or=90 and 50% for bulaquine and primaquine, respectively. Linearity in plasma was observed over a dynamic range of 1.56-400 and 3.91-1000 ng/ml for bulaquine and primaquine, respectively.

Animals↗
PubMed2003

In situ absorption and protein binding characteristics of CDRI-85/92, an antiulcer pharmacophore.

CDRI-85/92, a new antiulcer drug, acts as a proton pump inhibitor arresting the secretion of acid in the stomach. The absorption kinetics of CDRI-85/92 was evaluated in situ using rat intestinal recirculation perfusion method. The experiment was conducted at pH 2.6 and 7.4 representing the acidic and the mild alkaline environment, which the drug experiences through the GIT during oral treatment. The rate of absorption was the same (0.12h(-1)) at pH 2.6 and 7.4, thus suggesting equal absorption profile of the CDRI-85/92 throughout the GIT irrespective of the pH. Equal rates of absorption can also be correlated with the presence of acidic and basic groups in the structure of CDRI-85/92. Protein binding studies of CDRI-85/92 using ultrafiltration were conducted in vitro and in vivo. Protein binding was found to be in the range of 31.49-32.91% both in in vitro and in vivo (employing 5-min post dose samples of rat serum after 20 mgkg(-1) i.v. treatment of CDRI-85/92). The binding was found to be linear in the concentration range of 156.25-2000 ngml(-1) (r(2)>0.99).

Absorption↗
PubMed2003

Liquid chromatographic-mass spectrometric method for the determination of alpha-,beta-arteether in rat serum.

This study reports the development and validation of a sensitive and selective assay method for the determination of alpha-,beta-arteether in rat serum by liquid chromatography-mass spectrometry. The mobile phase was composed of methanol-0.1 mM sodium acetate (pH 5) (80:20%) at a flow-rate of 1 ml min(-1) and chromatographic separations were achieved on a Ultracarb, 5 ODS 20, Phenomenex column (5 micrometer, 30 mmx4.6 mm I.D.). The total effluent from the column was split so that one-tenth was injected into the electrospray LC-MS interface. ESI-MS analysis was carried out using a Micromass Quattro II Triple Quadrupole Mass Spectrometer equipped with an electrospray source. The MS analysis was carried out at a cone voltage of 52 V with a scan range of 100-400 Da. The analytes were quantified from the [M+Na](+) ion chromatograms of alpha-,beta-arteether at m/z 335 and artemisinin at m/z 305. A simple liquid-liquid extraction with 2x2 ml n-hexane was used to isolate alpha-,beta-arteether from rat serum. The method was validated in terms of recovery, linearity, accuracy and precision (within- and between-assay variation). The recovery from spiked control samples ranged from 88.41 to 96.17% with a maximum CV of 10.8% for alpha-arteether and 69.83-79.69% with a maximum CV of 17.06% for beta-arteether. Linearity in serum was observed over the range 20-320 ng ml(-1). Percent bias (accuracy) was well within the acceptable range. Within- and between-assay precision were less than 15%. The assay method described here is being applied to study the pharmacokinetics of CDRI developed intramuscular formulation Emal (alpha-/beta-arteether in the ratio of 30:70) in rats. The method is sensitive enough to monitor alpha-,beta-arteether up to 24 h after a single 30 mg kg(-1) i.m. dose.

Animals↗